Characterisation and origin of rust and powdery mildew resistance genes in VPM1 wheat

Summary The expression of rust resistances conferred by closely linked genes derived from VPM1 varied with environmental conditions and with genetic backgrounds. Under low light and low temperature conditions seedlings carrying Yr17 showed susceptible responses. Stem rust and leaf rust resistance genes Sr38 and Lr37 tended to confer more resistance at 17±2° C than at normal temperatures above > 20° C. These studies supported the hypothesis that Yr17, Lr37 and Sr38 were derived from Aegilops ventricosa, whereas Pm4b was probably derived from T. persicum. Studies on certain addition lines and parental stocks indicated that wheat cytoplasm may enhance the expression of Sr38.     

The frequency of natural cross-fertilisation in sequential sowings of winter barley

Summary Estimations of random mating frequency were computed for a series of sequential autumn sowings of populations of winter barley. The estimations were by means of the maximum likelihood scoring method and three varieties, each carrying a recessive genetic marker, provided three independent estimations for each population. High levels of out-crossing were found in sowings made early in September, and a trend towards absence of out-crossing in populations sown in late November was evident. Although fluctuations in this trend could be accounted for by fluctuations in meteorological factors, a more profound underlying effect was evident in that the three marker varieties behaved similarly, though to different degrees. It is postulated that the principle effect of sowing date, as it affects out-crossing, is upon the development of the flowering apex, and that environmental conditions at flowering time merely modify flowering behaviour.     

The Use of Multivariate Analyses to Eliminate Redundant Variables when Evaluating Potatoes for Chip Quality

Selection for good chipping clones in potato breeding often takes place during the middle and late selection stages. This is due to the considerable resources needed for the assessment of several characteristics. Objective multivariate methods for the elimination of redundant variables were applied to eight standardized chipping quality traits recorded on advanced clones over 15 years at two locations in New Brunswick, Canada. The clones were evaluated of specific gravity and the following chipping scores: direct from the field in August; after 10 days storage at 13 °C; from 4 °C storage in February; from 4 °C storage in February with 1 week, 2 weeks, 3 weeks and 4 weeks reconditioning at 16 °C. Five elimination methods produced a similar deletion order. In every subset obtained, specific gravity and direct chipping from the field were always retained. Reconditioning treatments from one to four weeks after cold storage were shown to be the most redundant. The reduction in the number of traits from eight to four by every technique could recover more than 80 % of the original variation, showing that redundant variables were effectively discarded.     

稀燃汽油机瞬态空燃比的滑模-神经网络控制

提出了稀燃汽油机空燃比滑模-神经网络控制方案,采用滑模变结构控制对稀燃工况的空燃比进行反馈控制,采用神经网络实现对进气量的精确预测和油膜动态特性的前馈补偿,进而实现对稀燃发动机瞬态空燃比的精确控制。采用自行开发的电控系统,在一台稀燃发动机上进行了瞬态空燃比实验。实验结果表明:节气门急速变化时空燃比超调可以控制在1个空燃比单位以内,调整时间不超过3s;转速越低,节气门变化越剧烈;空燃比超调越大,调整时间越长。     

曹娥江上游支流水环境容量的研究

本文针对我国东部地区典型河流-曹娥江的污染现状，选其上游支流长昭水库至南津桥河段进行了水环境容量研究，根据该河段的水流特性和水文、污染源的调查资料及水质实测资料，应用数学模型，分段研究了该河段各月的水环境容量。结果表明：该河段局部水质污染严重，水环境容量所剩无几。本项目的研究为实施污染物总量控制提供基础资料，为曹娥江流域水污染控制的管理和决策提供了科学依据。     

石油污染土壤降解与土壤的环境关系

阐述了石油污染土壤的降解与土壤环境的关系;提出如何消除石油污染土壤降解的环境限制因子,为微生物降解石油提供最理想环境,是有效治理石油污染的关键.     

突发性环境污染事故应急监测的速度保障

针对突发性环境事故如何保证应急监测速度的问题，从应急监测前准备工作及应急监测运行期两方面进行说明，为保障应急监测速度提供了切实可行的方法和步骤。     

生态脆弱地区的特殊旅游环保模式研究

摘要：基于生态脆弱地区环境的敏感性和不稳定性等特征,构建一种包括主动性保护、开发性保护及重建性保护三层结构的旅游环保模式。采用推理演绎及对比分析的研究方法,揭示传统旅游环保模式的环境保护与旅游开发的脱节性和环保行为的滞后性缺陷,虽然其已有部分程度上的脱节性改善,但仍不适用于生态脆弱地区的旅游环境保护。而较为有效的模式应是将旅游开发与环境保护更加充分地结合,甚至环境保护工作要占较大比例或超前进行,而且环境保护工作的重点要向以开发行为的外界输入促进环境改善和环境重建的方向转变。     

安全环保型蛋鸡饲料配方的筛选与应用

在优化出海兰灰蛋鸡氨基酸模型的基础上,确立了日粮低蛋白水平15%、14%的试验;集成和优化了蛋鸡安全环保型日粮的配方和添加剂组合(包括复合酶、植酸酶、益生素、果寡糖、除臭灵等),开发出了产蛋鸡安全环保1%预混合饲料,使用该环保添加剂,在生产性能不降低的前提下,可使蛋鸡粪便氮、磷排出量分别降低;同时蛋壳质量和鸡蛋品质得到改善。     

浅析竹类植物的城市生态环境效应

竹子具有显著的生态效应，在生态建设中发挥着巨大的作用。在总结有关竹类植物生态效应研究成果的基础上，针对现代城市环境特点，着重分析竹类植物对城市环境的生态作用，指出在城市生态环境建设中应重视竹类植物的运用及其生态功能的持续有效发挥。